naturemike
Level 1
(9 points)
Q: OSX unexpectedly shut down and restarted but will not reboot. Colored lines on screen
Hello,
I'm using OSX 10.10.5 (I think) At the very least I'm using EL Capitan. I cannot say the exact version since my computer will not boot up properly. The software is installed on an I mac from sometime around mid 2011.
The day started off like any other day. I turned on the computer. Opened the web browser and lightroom. All of a sudden my screen turned gray and my second display had a line down the middle almost as if two desktop screens were being displayed on one monitor. The screens flashed a few times with some funky patterns and then the who system restarted with a chime.
When it did, white vertical bands were running down the screen while the apple was being displayed during startup. The screen turned sold gray and then restarted again. This time the bands were purple. The same thing happened again but the next time the lines were orange and the system restarted a third time. At this point I turned the computer off and tried to start fresh but I was instantly greeted with more orange bands.
Can anyone help me find a solution or help me pin point the problem?
iMac, OS X El Capitan (10.11.5), 3.4 Ghz Intel Core i7, 32 GB of Ram
John Galt
Level 9
(50,394 points)
From what you describe, it sounds like a hardware problem that only Apple will be able to fix, but don't give up hope just yet.
Please read Get help with video issues on external displays connected to your Mac - Apple Support.
I realize the title and subject are not relevant to your concern, but buried within that document is the following passage containing three links describing the steps to follow.
If you can't change the resolution of your display because you can't see an image, restart your Mac in safe mode to reset the display resolution to defaults.
If starting in safe mode doesn't resolve the issue, reset your Mac's NVRAM and SMC to reset the video ports on your Mac to their defaults.
Do that first, then write back for additional suggestions if you still experience trouble.
